Electromagnetic scanning imager

Abstract

In one aspect, the present invention provides an imager, preferably portable, that includes a source of electromagnetic radiation capable of generating radiation with one or more frequencies in a range of about 1 GHz to about 2000 GHz. An optical system that is optically coupled to the source focuses radiation received therefrom onto an object plane, and directs at least a portion of the focused radiation propagating back from the object plane onto an image plane. The imager further includes a scan mechanism coupled to the optical system for controlling thereof so as to move the focused radiation over the object plane. A detector optically coupled to the lens at the image plane detects at least a portion of the radiation propagating back from a plurality of scanned locations in the object plane, thereby generating a detection signal. A processor that is in communication with the detector generates an image of at least a portion of the object plane based on the detection signal.

1 . An imaging system, comprising a housing adapted for positioning on a surface, said housing comprising:
 a source of electromagnetic radiation for generating radiation with one or more frequencies in a range of about 2 GHz to about 100 GHz,   an optical system optically coupled to said source so as to focus radiation received therefrom onto an object plane, said optical system directing at least a portion of the focused radiation propagating back from the object plane onto an image plane,   a scan mechanism coupled to the optical system for receiving radiation therefrom and/or directing radiation thereto, said scan mechanism effecting the scanning of the focused radiation over a two-dimensional portion of the object plane, said housing, optical system, and scan mechanism remaining translationally stationary relative to said surface as said scan mechanism effects the scanning of the radiation,   a detector optically coupled to said optical system at the image plane to detect at least a portion of the radiation propagating back from a plurality of scanned locations in the object plane, thereby generating a detection signal, and   a processor in communication with the detector to generate an image of at least a portion of the object plane based on said detection signal.   
     
     
         2 . The imaging system of  claim 1 , wherein said scan mechanism comprises two rotatable reflective elements, said elements comprising generally planar reflective surfaces, each of said elements configured to rotate about a respective rotation axis, said axes being substantially parallel to their respective planar surfaces, the two axes being substantially orthogonal with respect to each other. 
     
     
         3 . The scan mechanism of  claim 2 , wherein the reflective elements are disposed optically in series. 
     
     
         4 . The scan mechanism of  claim 2 , wherein the reflective elements comprise a two-dimensional raster scanner. 
     
     
         5 . The scan mechanism of  claim 2 , wherein the reflective elements comprise a two-dimensional spiral scanner. 
     
     
         6 . The scan mechanism of  claim 2 , wherein the reflective elements comprise a floret scanner. 
     
     
         7 . The scan mechanism of  claim 1 , wherein said scan mechanism comprises two rotatable reflective elements, said elements comprising substantially planar surfaces, said elements configured individually to rotate about rotation axes, said axes disposed at an angle with respect to the normals to the planar surfaces. 
     
     
         8 . The imaging system of  claim 1 , further comprising one or more position sensors coupled to said scan mechanism for determining a two-dimensional position thereof relative to a reference position. 
     
     
         9 . The imaging system of  claim 1 , further comprising a display in communication with said processor for displaying said image. 
     
     
         10 . The imaging system of  claim 1 , wherein said processor maps a variation of said detection signal to said scanned locations so as to generate said image. 
     
     
         11 . The imaging system of  claim 9 , wherein for each image point coordinate corresponding to one of the scanned locations, the display presents a brightness proportional to a strength of the detection signal corresponding to back-propagating radiation from that scanned location. 
     
     
         12 . The imaging system of  claim 1 , wherein said radiation source and said detector are formed as a single transmit/receive module operating in said frequency range of about 2 GHz to about 100 GHz. 
     
     
         13 . The imaging system of  claim 1 , wherein said housing is a portable housing. 
     
     
         14 . The imaging system of  claim 13 , further comprising an electronic processor and display module (EPDM) that includes said processor. 
     
     
         15 . The imaging system of  claim 14 , wherein said EPDM is integrated within said portable housing. 
     
     
         16 . The imaging system of  claim 15 , further comprising a second housing, separate from the portable housing, for containing said EPDM, said second housing being in data or signal communication with said portable housing. 
     
     
         17 . The imaging system of  claim 14 , wherein said EPDM comprises a display module for displaying said image. 
     
     
         18 . The imaging system of  claim 1 , further comprising a mechanism coupled to the source for modulating frequency of radiation generated by the source. 
     
     
         19 . The imaging system of  claim 18 , wherein said mechanism modulates the radiation frequency at a rate of about 100 kHz. 
     
     
         20 . A method of imaging, comprising:
 providing a housing adapted for positioning on a surface over an object plane and having a source of electromagnetic radiation for generating radiation with one or more frequency components in a range of about 2 GHz to about 100 GHz,   providing a focusing element in said housing that is optically coupled to said source,   utilizing the focusing element to focus radiation from the source onto the object plane,   utilizing a scan mechanism to effect scanning of the focused radiation over at least a two-dimensional portion of the object plane so as to illuminate a plurality of locations over a two-dimensional region of the object plane, said scan mechanism receiving radiation from said source and/or directing radiation to said source, said housing, focusing element, and scan mechanism remaining translationally stationary relative to said surface as said scan mechanism effects the scanning of the radiation,   detecting at least a portion of the radiation propagating back from said illuminated locations on the object plane thereby generating a time-dependent detection signal, and   analyzing said detection signal and said signals generated by said at least one sensor to form an image of the scanned portion of the object plane.   
     
     
         21 . The method of  claim 20 , wherein the step of focusing radiation further comprises directing the radiation to the object plane along a direction forming a non-zero angle relative to a normal to the object plane. 
     
     
         22 . The method of  claim 21 , wherein said angle is about 7 degrees. 
     
     
         23 . The imaging system of  claim 1 , wherein said source of electromagnetic radiation is adapted to generate radiation with one or more frequencies in a range of about 2 GHz to about 24 GHz. 
     
     
         24 . The imaging system of  claim 1 , wherein said source of electromagnetic radiation is adapted to generate radiation with one or more frequencies in a range of about 24 GHz to about 100 GHz. 
     
     
         25 . The method of  claim 20 , wherein said source of electromagnetic radiation is adapted to generate frequency components in a range of about 2 GHz to about 24 GHz. 
     
     
         26 . The method of  claim 20 , wherein said source of electromagnetic radiation is adapted to generate frequency components in a range of about 24 GHz to about 100 GHz.